NOISE MUFFLER FOR MAGNETIC TAPE VACUUM COLUMN

摘要

Noise in the frequency range of 60 to 3,000 Hz generated by movement of magnetic tape in a vacuum column is muffled by use of Helmholtz cavities. The connecting ports to the cavities are placed near the top of the vacuum column close to the source of the noise and also where they provide an impedance mismatch barrier to sound waves trying to exit from the top of the vacuum column. The size of the ports and location of the ports in the vacuum columns are predetermined so that the ports will not inhibit the loading of the tape loop into the vacuum column.